The reaction of motor industry lobbyists suggests the Government's changes to the warrant of fitness system are as radical as they are ill-considered. Far from it. The new rules are the least extreme of the options that were considered, and remain more stringent than those in many comparable countries. They also represent a reasonable balance between safety, the prime consideration, and cost savings. In sum, the Government has acted appropriately in responding to the great improvements in vehicle safety since six-monthly inspections were introduced in the 1930s.

From July next year, annual checks will be introduced for cars registered after 2000, while new cars will not need to be inspected for three years. Six-monthly inspections will remain for cars registered before January, 2000. With some testing stations now charging up to $50 for checks, it is estimated that motorists will benefit to the tune of $159 million a year. On the other side of the coin, some stations will be forced to close, with losses of jobs, and the cost of each inspection is likely to increase.

Change, however, is necessary. There is no reason New Zealand motorists should have to endure more frequent warrant of fitness checks than their counterparts overseas. Once, in the days of high import costs, this country's car fleet was noticeably aged and, therefore, more prone to defects that could result in serious accidents. But two things have happened. First, our fleet now bears a far greater resemblance to those overseas in terms of age. Second, cars have become far more reliable. Frequent inspections are not a panacea. The number of accidents linked to vehicle faults here is the same as in other countries at about 2.5 per cent - or 0.5 per cent where they are the only cause. Liquor and speed are far greater factors.

Equally, however, it is appropriate to continue six-monthly checks for cars registered before 2000. While it is possible to argue that more frequent inspections should kick in earlier - say, after eight years - data from New Zealand crashes show the risk of defect-related accidents begins to increase more steeply when cars are about 12 years old. Drivers of older cars, rather than complaining about discrimination, should regard the more frequent tests as offering reassurance about their vehicles' safety.

The presence of these older cars persuaded the Government, quite rightly, to reject more liberal warrant of fitness options. One of these was the system in place in some states of Australia, under which inspections are required only on change of ownership. This places responsibility on owners to ensure their cars are well maintained. New Zealanders, however, are licensed to drive at a relatively young age. Many at that time of their lives have neither the maturity nor the money to maintain their cars properly.

Even so, the new system will throw a greater responsibility on motorists. They must have a greater awareness of when their tyres are almost bald or when their brakes are starting to fail. The Government says it will address this with education campaigns intended to ram home the importance of maintenance and with more funding for police enforcement. The significance of these should not be underestimated.

Other countries give their police substantial powers to order dangerous cars off the road. The Government has also decided there will be no demerit points for those caught operating unsafe cars. Such lenience makes it all the more important that the new regime is closely monitored. The bottom line is that the current level of road safety must be maintained. It appears unlikely that this will be compromised, but the Government must be alert to any unforeseen repercussions.